it's a rev. b imac g5 (ambient light sensor, no isight). 20" model, 8x super drive. it seems to read dvds no problem, but cds it will just keep trying to read, fail, and spit them out. they sometimes eventually work after many many many many many MANY tries, but that is no good. any ideas on what the problem might be? any ideas for solutions?

I have pretty much the same machine as you, except that mine is 17". I had a similar problem, but it turned out that the CDs were slightly scratched, or of otherwise poor quality. I guess the drive is really sensitive to imperfections.